Polymer coated sulfonated polyester—silver nanoparticle composite filaments and methods of making the same

ABSTRACT

A composite filament includes a core particle comprising a sulfonated polyester matrix and a plurality of silver nanoparticles dispersed within the matrix, and a shell polymer disposed about the core particle, and methods of making thereof. Various articles can be manufactured from such composite filaments.

CROSS-REFERENCE TO RELATED APPLICATIONS

Reference is made to commonly owned and co-pending, U.S. patentapplication Ser. No. 15,098,280 entitled STYRENIC-BASED POLYMER COATEDSILVER NANOPARTICLE-SULFONATED POLYESTER COMPOSITE POWDERS AND METHODSOF MAKING THE SAME” to Valerie M. Farrugia et al., electronically filedon the same day herewith, the entire disclosures of which areincorporated herein by reference in its entirety.

BACKGROUND

The present disclosure relates to composite filaments, particularly,filaments of polymer coated composite comprising metal nanoparticlesdispersed throughout the composite matrix, for use in Fused DepositionModelling (FDM).

The medical community's reliance on three dimensional 3D printing forvarious applications is rapidly increasing and covers areas such astissue and organ fabrication, customizable devices such as prosthetics,mouth guards, orthotics, hearing aids and implants, and pharmaceuticalexploration related to controlled drug delivery and personalized drugproduction. Many of these medical applications require compositematerial that can inhibit bacterial, microbial, viral or fungal growth.Other products for 3D printing such as kitchen tools, toys, educationmaterials and countless household items also provide a favorableenvironment for bacteria growth, and therefore antibacterial compositematerials are also desirable for use in connection with these products.Due to the layered construction of 3D printed material, the potentialfor bacterial growth can be very significant, especially since certainbacterial strains can actually thrive within the detailed structuralmake-up of these materials. Washing alone does not completely sterilizethe surfaces and crevasses of these products.

Therefore, there exists a need for new materials with antibacterialproperties for 3D printing. One of the 3D printing methods is FDM, whichis a common additive manufacturing (3D printing) technique. FDM is anadditive layer manufacture technology for fabricating physical, 3Dobjects from computer-aided-design (CAD) models. FDM technology canprocess common 3D printing materials, such as, polylactic acid (PLA),acrylonitrile butadiene styrene (ABS), and high-density polyethylene(HDPE). FDM operates on the principle of heating and then extruding afeedstock material, typically as a series of stacked, patterned layers,thereby to form a build. FDM process employs moltenthermoplastic/polymers as build materials for making 3D articles via theextrusion of the molten plastics. This modelling process is a multi-stepapproach where a computer-aided design is rendered, in the case ofmedical applications this model would come from an ultrasound, computedtomography scan or magnetic resonance image. This design is thenprocessed by software which sets the desired build parameters. The filedata is used by the FDM apparatus to build the article. The spool offilament material is fed into a headed extrusion head which delivers thesemi-liquid material onto the build platform in a layer-by-layerfashion. As the model is built, the layers solidify upon deposition dueto the temperature differential of the build chamber. In some cases thehead can also extrude a removable support material which acts as ascaffold to hold the article layers in place as it cools. This supportmaterial can later be removed via heating, breaking off or washing (inultrasonic vibration tank). A layer by layer method of depositingmaterials for building a model is described in U.S. Pat. No. 5,121,329which is incorporated herein by reference. Examples of apparatus andmethods for making three-dimensional models by depositing layers offlowable modeling material are described in U.S. Pat. No. 4,749,347,U.S. Pat. No. 5,121,329, U.S. Pat. No. 5,303,141, U.S. Pat. No.5,340,433, U.S. Pat. No. 5,402,351, U.S. Pat. No. 5,503,785, U.S. Pat.No. 5,587,913, U.S. Pat. No. 5,738,817, U.S. Pat. No. 5,764,521 and U.S.Pat. No. 5,939,008. An extrusion head extrudes heated, flowable modelingmaterial from a nozzle onto a base The base comprises a modelingsubstrate which is removably affixed to a modeling platform. Theextruded material is deposited layer-by-layer in areas defined from theCAD model, as the extrusion head and the base are moved relative to eachother in three dimensions by an x-y-z gantry system. The materialsolidifies after it is deposited to form a three-dimensional model. Itis disclosed that a thermoplastic material may be used as the modelingmaterial, and the material may be solidified after deposition bycooling.

SUMMARY

In some aspects, embodiments herein relate to composite filamentcomprising a core particle and a shell polymer disposed about the coreparticle, wherein the core particle comprising a sulfonated polyestermatrix; and a plurality of silver nanoparticles dispersed within thematrix; wherein the silver nanoparticle is present in the compositefilament in a range from about 0.5 ppm to about 50,000 ppm; and furtherwherein the composite filament has a diameter of from about 0.5 mm toabout 5 mm.

In some aspects, embodiments herein relate to method of producing acomposite filament comprising heating a sulfonated polyester resin in anorganic-free solvent; adding a solution of silver (I) ion to the heatedresin in the organic-free solvent to form a mixture; adding a solutionof a reducing agent to the mixture, thereby forming an emulsion of coreparticles comprising a sulfonated polyester matrix and a plurality ofsilver nanoparticles disposed within the sulfonated polyester matrix;adding a styrene monomer and initiator to the emulsion of core particlesto form a shell polymer disposed about the core particles, therebyforming a composite structure; aggregating the emulsion of compositeparticles to form aggregated particles; coalescing the aggregatedparticles to form coalesced particles; washing the coalesced particles,thereby forming a composite powder; and extruding the composite powderto produce the composite filament.

In some aspects, embodiments herein relate to an article comprising acomposite filament comprising a core particle and a shell polymerdisposed about the core particle, wherein the core particle comprising asulfonated polyester matrix; and a plurality of silver nanoparticlesdispersed within the matrix; wherein the silver nanoparticle is presentin the composite filament in a range from about 0.5 ppm to about 50,000ppm; and further wherein the composite powder has a particle size offrom about 10 microns to about 300 microns.

BRIEF DESCRIPTION OF DRAWINGS

Various embodiments of the present disclosure will be described hereinbelow with reference to the figures wherein:

FIGS. 1A and 1B shows a schematic of a possible mechanism of styrenationof sulfonated polyester silver nanoparticles (AgNP) in an aqueous mediumaccording to embodiments described herein.

FIGS. 2A and 2B show a schematic of a possible mechanism of thepreparation of dry particles for filament fabrication.

FIG. 3 shows a Transmission Electron Microscopy (TEM) image of anexemplary composite structure (Example 4) comprising a styrene-coated,sulfonated polyester-AgNP composite structure. Dark areas are AgNPs.

DETAILED DESCRIPTION

As used herein, “a,” “an,” “the,” “at least one,” and “one or more” areused interchangeably. Thus, for example, a coating composition thatcomprises “an” additive can be interpreted to mean that the coatingcomposition includes “one or more” additives.

Also herein, the recitations of numerical ranges includes disclosure ofall subranges included within the broader range (e.g., 1 to 5 discloses1 to 4, 1 to 3, 1 to 2, 2 to 4, 2 to 3, . . . etc.).

The present disclosure provides a composite filament, more specifically,a filament of a polymer coated sulfonated polyester polymeric compositecontaining silver nanoparticles (AgNPs), for use in Fused DepositionModelling (FDM) application.

The class of AgNP polymer composites is more suitable for antibacterialapplications compared to ionic and bulk silver, because silver salts mayrelease silver too quickly and uncontrollably while bulk silver is veryinefficient in releasing active silver species. AgNPs are known fortheir antibacterial properties; however the exact mechanism ofantibacterial activity using AgNPs is poorly understood. The AgNPs mayinteract with the cell wall of the bacteria, consequently destabilizingthe plasma-membrane potential and reducing the levels of intracellularadenosine triphosphate (ATP) resulting in bacterial cell death.Alternatively, AgNPs might play a role in the formation of reactiveoxygen species (ROS) which is responsible for the cytotoxicity ofbacteria cells in presence of AgNPs. “Potential Theranostics Applicationof Bio-Synthesized Silver Nanoparticles (4-in-1 System),” Theranostics2014; 4(3):316-335. Furthermore, AgNPs have been reported to take partin chemical reduction-oxidation reactions as a catalyst by facilitatingelectron transfer between an electron donor and electron acceptor.“Micelle bound redox dye marker for nanogram level arsenic detectionpromoted by nanoparticles,” New J. Chem., 2002, 26, 1081-1084.

The FDM composite filament of the present disclosure may be synthesizedfrom sulfonated polyester-silver nanoparticles (SPE-AgNPs, where theSPE-AgNPs are aggregated from nano-sized to micron-sized then extrudedinto filaments. More specifically, a dry composite powder is firstformed from the aggregation of self-dispersible sulfonated polyester(SPE) with embedded silver nanoparticles (AgNPs) that are simultaneouslyproduced from silver nitrate with or without a reducing agent during theself-assembly of the sulfonated polyester resin particles in water.Subsequently, the dry composite powder is then processed into filamentsfrom its powdered form, where the powdered form may optionally includeadditives and/or fillers. The present disclosure pertain to polymericfilaments comprising a sulfonated polyester matrix and a plurality ofsilver nanoparticles may be prepared according to procedures disclosedin U.S. Pat. No. 6,866,807, U.S. Pat. No. 5,121,329, U.S. Pat. No.6,730,252, U.S. Pat. No. 3,046,178, U.S. Pat. No. 6,923,634, U.S. Pat.No. 2,285,552, U.S. Pat. No. 4,012,557, U.S. Pat. No. 4,913,864, USPatent Publication 20040222561, and US Patent Publication 20150084222.

Polymeric Coated Sulfonated Polyester-Silver Nanoparticles SPE-AgNPs

Certain embodiments herein provide methods of synthesizing silvernanoparticles (AgNPs) by reduction of silver (I) ion simultaneouslyduring the self-assembly of sodio sulfonated polyester resin particlesin water. The methods which employ water as the bulk solvent areenvironmentally friendly being free of organic solvents (or organic-freesolvents). The methods are efficient requiring minimal time to preparethe polymer metal nanocomposites. Without being bound by theory it ispostulated that silver ions are trapped within the polymer matrix duringthe self-assembly of the sodio sulfonated polyester while simultaneouslybeing reduced to AgNPs. The sulfonated polyester-silver nanoparticles(SPE-AgNPs) are simultaneously synthesized during the self-assembly ordispersing of polymer in water as indicated in FIG. 1. Thus, the sodiosulfonated polyester serves as both a carrier for the silver ions and anorganic matrix for the in situ synthesis of silver nanocomposites. Anoptional reducing agent is added during the self-assembly of sodiosulfonated polyester to reduce silver nitrate into silver nanoparticles(AgNPs) resulting in well dispersed particles. The polyester matrixplays an important role as it is postulated to inhibit the agglomerationof AgNPs. Meanwhile, the porosity of the sulfonated polyester allows thesilver ions to diffuse and/or absorb throughout the polymer matrixallowing unhindered interaction with the sulfonate functional groups ofthe polyester. The reducing agent employed in the reduction of silverion also freely diffuses throughout the polyester matrix and promotesthe formation of well-dispersed AgNPs on the surface and interior of thepolyester particles. Advantageously, the process minimizes nanoparticleagglomeration that plagues conventional methods with pre-formednanoparticles. The sulfonated polymer matrix has an important role inkeeping the AgNPs dispersed as well as maintaining overall chemical andmechanical stability of the composite. A polystyrene shell may be thenformed on the surface of the SPE-AgNPs. When a hydrophobic monomer, suchas styrene is added, it polymerizes around the hydrophobic SPE core ofthe SPE nanosphere and forms a polystyrene shell on the surface of theSPE-AgNPs. The styrene monomer may also diffuse within the porous SPEcore. The sulfonated polyester plays a critical role as a stabilizer forin-situ synthesized AgNPs and also as a nano-template to provide afavorable environment for the polymerization of styrene in water withoutthe use of a surfactant.

Silver has many useful properties, including its antibacterial,antimicrobial, antifungal, antiviral properties. These novel propertiesof the silver nanocomposite materials disclosed herein make them usefulin medical applications and others as described herein.

The sulfonated polyester resins disclosed herein have been selected tohave a hydrophobic backbone while presenting hydrophilic sulfonategroups attached along the chain. Without being bound by theory, whenplaced in water and heated, the hydrophobic portions may interact witheach other to form a hydrophobic core with the hydrophilic sulfonategroups facing the surrounding water resulting in the sulfonatedpolyester self-assembling into a higher order, spherical nanoparticlewithout the requirement of additional reagents. Thus, there is a higherorder involving the amphiphilic polyester, in which the hydrophobicbackbone, which is insoluble in water, and the water-soluble hydrophilicsulfonate groups, operate as macrosurfactants. This results inself-association, self-assembly, self-dispersible nanoparticles inaqueous medium to yield micelle-like aggregates. The formation of silvernanoparticles within and surrounding the micelles is a secondaryoccurrence upon addition of silver nitrate and reducing agent.

In embodiments, there are provided composites comprising a sulfonatedpolyester matrix, and a plurality of silver nanoparticles dispersedwithin the matrix.

In embodiments, the sulfonated polyester matrix is a branched polymer(BSPE). In embodiments, the sulfonated polyester matrix is a linearpolymer. The selection of branched or linear polymer may depend on,inter alia, the downstream application of the composite product. Linearpolymers can be used to create strands of fibers or form a strongmesh-like structure. Branched polymers may be useful to conferthermoplastic properties on the resultant composite material.

In embodiments, sulfonated polyesters of the present disclosure can be ahomopolymer of one ester monomer or a copolymer of two or more estermonomers. Examples of suitable sulfonated polyesters include thosedisclosed in U.S. Pat. Nos. 5,348,832, 5,593,807, 5,604,076, 5,648,193,5,658,704, 5,660,965, 5,840,462, 5,853,944, 5,916,725, 5,919,595,5,945,245, 6,054,240, 6,017,671, 6,020,101, 6,140,003, 6,210,853 and6,143,457, the disclosures of each of which are totally incorporatedherein by reference.

In embodiments, sulfonated polyesters of the present disclosure can behydrogen or a salt of a random sulfonated polyester, including salts(such as metal salts, including aluminum salts, salts of alkali metalssuch as sodium, lithium, and potassium, salts of alkaline earth metalssuch as beryllium, magnesium, calcium, and barium, metal salts oftransition metals, such as vanadium, iron, cobalt, copper, and the like,as well as mixtures thereof) of poly(1,2-propylene-5-sulfoisophthalate),poly(neopentylene-5-sulfoisophthalate),poly(diethylene-5-sulfoisophthalate),copoly(1,2-propylene-5-sulfoisophthalate)-copoly-(1,2-propylene-terephthalatephthalate),copoly(1,2-propylene-diethylene-5-sulfoisophthalate)-copoly-(1,2-propylene-diethylene-terephthalatephthalate),copoly(ethylene-neopentylene-5-sulfoisophthalate)-copoly-(ethylene-neopentylene-terephthalate-phthalate),copoly(propoxylated bisphenol A)-copoly-(propoxylated bisphenolA-5-sulfoisophthalate),copoly(ethylene-terephthalate)-copoly-(ethylene-5-sulfo-isophthalate),copoly(propylene-terephthalate)-copoly-(propylene-5-sulfo-isophthalate),copoly(diethylene-terephthalate)-copoly-(diethylene-5-sulfo-isophthalate),copoly(propylene-diethylene-terephthalate)-copoly-(propylene-diethylene-5-sulfoisophthalate),copoly(propylene-butylene-terephthalate)-copoly(propylene-butylene-5-sulfo-isophthalate),copoly(propoxylated bisphenol-A-fumarate)-copoly(propoxylated bisphenolA-5-sulfo-isophthalate), copoly(ethoxylatedbisphenol-A-fumarate)-copoly(ethoxylatedbisphenol-A-5-sulfo-isophthalate), copoly(ethoxylatedbisphenol-A-maleate)-copoly(ethoxylatedbisphenol-A-5-sulfo-isophthalate), copoly(propylene-diethyleneterephthalate)-copoly(propylene-5-sulfoisophthalate),copoly(neopentyl-terephthalate)-copoly-(neopentyl-5-sulfoisophthalate),and the like, as well as mixtures thereof.

In general, the sulfonated polyesters may have the following generalstructure, or random copolymers thereof in which the n and p segmentsare separated.

wherein R is an alkylene of, for example, from 2 to about 25 carbonatoms such as ethylene, propylene, butylene, oxyalkylenediethyleneoxide, and the like; R′ is an arylene of, for example, fromabout 6 to about 36 carbon atoms, such as a benzylene, bisphenylene,bis(alkyloxy) bisphenolene, and the like; and p and n represent thenumber of randomly repeating segments, such as for example from about 10to about 100,000.

Examples of the sulfonated polyesters further include those disclosed inU.S. Pat. No. 7,312,011 which is incorporated herein by reference in itsentirety. Specific examples of amorphous alkali sulfonated polyesterbased resins include, but are not limited to,copoly(ethylene-terephthalate)-copoly-(ethylene-5-sulfo-isophthalate),copoly(propylene-terephthalate)-copoly(propylene-5-sulfo-isophthalate),copoly(diethylene-terephthalate)-copoly(diethylene-5-sulfo-isophthalate),copoly(propylene-diethylene-terephthalate)-copoly(propylene-diethylene-5-sulfo-isophthalate),copoly(propylene-butylene-terephthalate)-copoly(propylene-butylene-5-sulfo-isophthalate),copoly(propoxylated bisphenol-A-fumarate)-copoly(propoxylated bisphenolA-5-sulfo-isophthalate), copoly(ethoxylatedbisphenol-A-fumarate)-copoly(ethoxylatedbisphenol-A-5-sulfo-isophthalate), and copoly(ethoxylatedbisphenol-A-maleate)-copoly(ethoxylatedbisphenol-A-5-sulfo-isophthalate), and wherein the alkali metal is, forexample, a sodium, lithium or potassium ion. Examples of crystallinealkali sulfonated polyester based resins alkalicopoly(5-sulfoisophthaloyl)-co-poly(ethylene-adipate), alkalicopoly(5-sulfoisophthaloyl)-copoly(propylene-adipate), alkalicopoly(5-sulfoisophthaloyl)-copoly(butylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(pentylene-adipate), and alkalicopoly(5-sulfo-isophthaloyl)-copoly(octylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(ethylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly (propylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-co-poly(butylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(pentylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(hexylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(octylene-adipate), alkalicopoly(5-sulfoisophthaloyl)-copoly(ethylene-succinate), alkalicopoly(5-sulfoisophthaloyl-copoly(butylene-succinate), alkalicopoly(5-sulfoisophthaloyl)-copoly(hexylene-succinate), alkalicopoly(5-sulfoisophthaloyl)-copoly(octylene-succinate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(ethylene-sebacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(propylene-sebacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(butylene-sebacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(pentylene-sebacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(hexylene-sebacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(octylene-sebacate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(ethylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(propylene-adipate), alkalicopoly(5-sulfo-iosphthaloyl)-copoly(butylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)-copoly(pentylene-adipate), alkalicopoly(5-sulfo-isophthaloyl)copoly(hexylene-adipate),poly(octylene-adipate), and wherein the alkali is a metal such assodium, lithium or potassium. In embodiments, the alkali metal issodium.

The sulfonated polyesters suitable for use in the present disclosure mayhave a glass transition (Tg) temperature of from about 45° C. to about95° C., or from about 52° C. to about 70° C., as measured by theDifferential Scanning calorimeter. The sulfonated polyesters may have anumber average molecular weight of from about 2,000 g per mole to about150,000 g per mole, from about 3,000 g per mole to about 50,000 g permole, or from about 6,000 g per mole to about 15,000 g per mole, asmeasured by the Gel Permeation Chromatograph. The sulfonated polyestersmay have a weight average molecular weight of from about 3,000 g permole to about 300,000 g per mole, from about 8,000 g per mole to about90,000 g per mole, or from about 10,000 g per mole to about 60,000 g permole, as measured by the Gel Permeation Chromatograph. The sulfonatedpolyesters may have a polydispersity of from about 1.6 to about 100,from about 2.0 to about 50, or from about 5.0 to about 30, as calculatedby the ratio of the weight average to number average molecular weight.

The linear amorphous polyester resins are generally prepared by thepolycondensation of an organic diol and a diacid or diester, at leastone of which is sulfonated or a sulfonated difunctional monomer beingincluded in the reaction, and a polycondensation catalyst. For thebranched amorphous sulfonated polyester resin, the same materials may beused, with the further inclusion of a branching agent such as amultivalent polyacid or polyol.

Examples of diacid or diesters selected for the preparation of amorphouspolyesters include dicarboxylic acids or diesters selected from thegroup consisting of terephthalic acid, phthalic acid, isophthalic acid,fumaric acid, maleic acid, itaconic acid, succinic acid, succinicanhydride, dodecylsuccinic acid, dodecylsuccinic anhydride, glutaricacid, glutaric anhydride, adipic acid, pimelic acid, suberic acid,azelic acid, dodecanediacid, dimethyl terephthalate, diethylterephthalate, dimethylisophthalate, diethylisophthalate,dimethylphthalate, phthalic anhydride, diethylphthalate,dimethylsuccinate, dimethylfumarate, dimethylmaleate, dimethylglutarate,dimethyladipate, dimethyl dodecylsuccinate, and mixtures thereof. Theorganic diacid or diester are selected, for example, from about 45 toabout 52 mole percent of the resin. Examples of diols utilized ingenerating the amorphous polyester include 1,2-propanediol,1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol,pentanediol, hexanediol, 2,2-dimethylpropanediol,2,2,3-trimethylhexanediol, heptanediol, dodecanediol,bis(hydroxyethyl)-bisphenol A, bis(2-hydroxypropyl)-bisphenol A,1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, xylenedimethanol,cyclohexanediol, diethylene glycol, bis(2-hydroxyethyl) oxide,dipropylene glycol, dibutylene, and mixtures thereof. The amount oforganic diol selected can vary, and more specifically, is, for example,from about 45 to about 52 mole percent of the resin.

Alkali sulfonated difunctional monomer examples, wherein the alkali islithium, sodium, or potassium, include dimethyl-5-sulfo-isophthalate,dialkyl-5-sulfo-isophthalate-4-sulfo-1,8-naphthalic anhydride,4-sulfo-phthalic acid, 4-sulfophenyl-3,5-dicarbomethoxybenzene,6-sulfo-2-naphthyl-3,5-dicarbomethoxybenzene, sulfo-terephthalic acid,dimethyl-sulfo-terephthalate, dialkyl-sulfo-terephthalate,sulfo-ethanediol, 2-sulfo-propanediol, 2-sulfo-butanediol,3-sulfo-pentanediol, 2-sulfo-hexanediol, 3-sulfo-2-methylpentanediol,N,N-bis(2-hydroxyethyl)-2-aminoethane sulfonate,2-sulfo-3,3-dimethylpent-anediol, sulfo-p-hydroxybenzoic acid, mixturesthereto, and the like. Effective difunctional monomer amounts of, forexample, from about 0.1 to about 2 weight percent of the resin can beselected.

Branching agents for use in forming the branched amorphous sulfonatedpolyester include, for example, a multivalent polyacid such as1,2,4-benzene-tricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid,2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylicacid, 1,2,5-hexanetricarboxylic acid,1,3-dicarboxyl-2-methyl-2-methylene-carboxylpropane,tetra(methylene-carboxyl)methane, and 1,2,7,8-octanetetracarboxylicacid, acid anhydrides thereof, and lower alkyl esters thereof, 1 toabout 6 carbon atoms; a multivalent polyol such as sorbitol,1,2,3,6-hexanetetrol, 1,4-sorbitane, pentaerythritol, dipentaerythritol,tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentatriol,glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol,trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene,mixtures thereof, and the like. The branching agent amount selected is,for example, from about 0.1 to about 5 mole percent of the resin.

Polycondensation catalyst examples for amorphous polyesters includetetraalkyl titanates, dialkyltin oxide such as dibutyltin oxide,tetraalkyltin such as dibutyltin dilaurate, dialkyltin oxide hydroxidesuch as butyltin oxide hydroxide, aluminum alkoxides, alkyl zinc,dialkyl zinc, zinc oxide, stannous oxide, or mixtures thereof; and whichcatalysts are selected in amounts of, for example, from about 0.01 molepercent to about 5 mole percent based on the starting diacid or diesterused to generate the polyester resin.

In particular embodiments, the sulfonated polyester matrix comprises apolyol monomer unit selected from the group consisting oftrimethylolpropane, 1,2-propanediol, diethylene glycol, and combinationsthereof.

In particular embodiments, the sulfonated polyester matrix comprises adiacid monomer unit selected from the group consisting of terephthalicacid, sulfonated isophthalic acid, and combinations thereof.

In embodiments, the sulfonated polyester-silver core nanoparticles mayhave a particle size in a range from about 5 nm to about 500 nm, orabout 10 to about 200 nm, or about 20 to about 100 nm. A core particlesize of less than 100 nm may be useful for reinforcement of polymermatrices without disturbing transparency and other properties ofcoatings. Tsavalas, J. G. et al. J. Appl. Polym. Sci., 87:1825-1836(2003). As used herein, references to “particle size” will generallyrefer to D₅₀ mass-median-diameter (MMD) or the log-normal distributionmass median diameter. The MMD is considered to be the average particlediameter by mass.

In embodiments, the silver nanoparticles may include solely elementalsilver or may be a silver composite, including composites with othermetals. Such metal-silver composite may include either or both of (i)one or more other metals and (ii) one or more non-metals. Suitable othermetals include for example Al, Au, Pt, Pd, Cu, Co, Cr, In, and Ni,particularly the transition metals for example Au, Pt, Pd, Cu, Cr, Ni,and mixtures thereof. Exemplary metal composites are Au—Ag, Ag—Cu,Au—Ag—Cu, and Au—Ag—Pd. Suitable non-metals in the metal compositeinclude for example Si, C, and Ge. The various components of the silvercomposite may be present in an amount ranging for example from about0.01% to about 99.9% by weight, particularly from about 10% to about 90%by weight. In embodiments, the silver composite is a metal alloycomposed of silver and one, two or more other metals, with silvercomprising for example at least about 20% of the nanoparticles byweight, particularly greater than about 50% of the nanoparticles byweight. Unless otherwise noted, the weight percentages recited hereinfor the components of the silver-containing nanoparticles do not includethe stabilizer.

Silver nanoparticles composed of a silver composite can be made forexample by using a mixture of (i) a silver compound (or compounds,especially silver (I) ion-containing compounds) and (ii) another metalsalt (or salts) or another non-metal (or non-metals) during thereduction step.

In embodiments, the silver nanoparticles have a particle size in a rangefrom about 2 to about 50 nm, or about 10 to about 50 nm or about 20 toabout 50 nm. Silver nanoparticles of diameter less than 100 nm absorblight primarily below 500 nm. This property is useful as it allows theAgNPs to be used in combination with fluorescence emission detectionsince most fluorophores emit at a wavelength above 500 nm, thusminimizing quenching of the signal.

In embodiments, the sulfonated polyester-silver core nanoparticles mayfurther comprise nanostructured materials, such as, without limitation,carbon nanotubes (CNTs, including single-walled, double-walled, andmulti-walled), graphene sheet, nanoribbons, nano-onions, hollownanoshell metals, nano-wires and the like. In embodiments, CNTs may beadded in amounts that enhance electrical and thermal conductivity.

A shell polymer may be disposed over the sulfonated polyester-silvercore nanoparticles to provide additional reinforcement in terms of thehardness, strength, chemical resistance and thermal stability of thesulfonated polyester-silver core/AgNP composite in extreme environments.

In embodiments, the shell polymer disposed about the sulfonatedpolyester-silver core nanoparticles comprises a styrene monomer,including substituted or unsubstituted styrenes. In embodiments, theshell polymer further comprises at least one vinyl monomer selected fromthe group consisting of methyl acrylate, ethyl acrylate, butyl acrylate,isobutyl acrylate, dodecyl acrylate, n-octyl acrylate, 2-ethylhexylacrylate, 2-chloroethyl acrylate, phenyl acrylate, β-carboxyethylacrylate, methyl α-chloro acrylate, methyl methacrylate, ethylmethacrylate, butyl methacrylate, butadiene, isoprene,methacrylonitrile, acrylonitrile, methyl vinyl ether, vinyl isobutylether, vinyl ethyl ether, vinyl acetate, vinyl propionate, vinylbenzoate, vinyl butyrate, vinyl methyl ketone, vinyl hexyl ketone, andmethyl isopropenyl ketone, vinylidene chloride, vinylidene chlorofluoride, N-vinylindole, N-vinyl pyrrolidene, acrylic acid, methacrylicacid, acrylamide, methacrylamide, vinyl pyridine, vinyl pyrrolidone,vinyl N-methylpyridinium chloride, vinyl naphthalene, p-chlorostyrene,vinyl chloride, vinyl fluoride, ethylene, propylene, butylene, andisobutylene.

In embodiments, the shell polymer has a thickness from about 0.5 nm toabout 100 nm, or from about 1.0 nm to about 50 nm, or from about 1.5 nmto about 20 nm.

In embodiments, the shell polymer confers to the sulfonatedpolyester-silver core nanoparticles one or more properties, such as,methanol resistance, resistance to thermal degradation, and acid/baseresistance.

With respect to methanol resistance, it is postulated that the polymershell protects the core sulfonated polyester/AgNP composite fromgelation. In embodiments, no more than about 10% material dissolveswhen, for example, a styrene shell is used.

With respect to resistance to thermal degradation, polymershell-protected composites show only about 50% degradation at 400° C.,while uncoated SPE-AgNP composites show about 80% decomposition at 400°C. The thermal stability of the styrene-coated composites, inparticular, appears to be more complex than that of polystyrene alone.

With respect to acid/base resistance, addition of a polymer shell, suchas styrene, to the core composite may provide an improvement under basicconditions by 20% to 30%. Finally, a polymer shell, such as polystyrene,around the SPE/AgNp core provides substantially improved rigidity andstrength of the organic/inorganic hybrid composite core materials.

Composite Filament Synthesized from Polymeric Coated SulfonatedPolyester-Silver Nanoparticles SPE-AgNPs

Composite powders as described herein are first prepared from thepolymeric coated sulfonated polyester-silver nanoparticles (SPE-AgNPs),and then the composite powders are converted to composite filaments byfilament fabrication.

Composite powders may be prepared by conventional (ground andclassification) or chemical (emulsion aggregation) means. U.S. Pat. Nos.5,111,998, 5,147,753, 5,272,034, and 5,393,630 disclose conventionaltoner manufacturing processes are incorporated in their entirety byreference herein.

Composite powders may be prepared by emulsion aggregation means. Anysuitable emulsion aggregation procedure may be used in forming theemulsion aggregation composite particles without restriction. FIG. 3shows an emulsion aggregation process for preparing dry particles forFused Deposition Modelling (FDM) according to certain embodiments of thepresent disclosure. These procedures typically include the process stepsof aggregating an emulsion of particles, such as those described in thepresent disclosure, a polymer coated core particle, where the coreparticle comprising a sulfonated polyester matrix and a plurality ofsilver nanoparticles disposed within the sulfonated polyester matrix,and one or more additional optional additives to form aggregatedparticles, subsequently coalescing the aggregated particles, and thenrecovering, optionally washing and optionally drying the obtainedemulsion aggregation particles. However, in embodiments, the process ismodified by the addition of a coalescent agent (or coalescence aidagent) prior to the coalescence. This addition of the coalescent agentprovides toner particles having improved spheroidization, and allows thecoalescence to be conducted in a shorter time, at a lower processtemperature, or both. In embodiments, prior to the aggregation step,water is added to the SPE-AgNPs to form a slurry. In embodiments, theaddition of water affords a total solid content based on the totalweight of the slurry of from about 1% to about 40%, from about 5% toabout 20%, or from about 10% to about 50%. The aggregating step includesheating the slurry to a temperature of from about 30° C. to about 80°C., from about 40° C. to about 70° C., or from about 50° C. to about 68°C. The duration of the aggregation step may be from about 1 minute toabout 8 hours, from about 30 minutes to about 6 hour, or from about 60minutes to about 4 hours. The coalescing step includes heating theaggregated particles to a temperature of from about 30° C. to about 95°C., from about 40° C. to about 95° C., or from about 60° C. to about 90°C. The duration of the coalescing step may be from about 1 minute toabout 6 hours, from about 30 minutes to about 4 hour, or from about 60minutes to about 3 hours.

Examples of suitable coalescent agents include, but are not limited to,benzoic acid alkyl esters, ester-alcohols, glycol-ether type solvents,long-chain aliphatic alcohols, aromatic alcohols, mixtures thereof, andthe like. Examples of benzoic acid alkyl esters include benzoic acidalkyl esters where the alkyl group, which can be straight or branched,substituted or unsubstituted, has from about 2 to about 30 carbon atoms,such as decyl or isodecyl benzoate, nonyl or isononyl benzoate, octyl orisooctyl benzoate, 2-ethylhexyl benzoate, tridecyl or isotridecylbenzoate, 3,7-dimethyloctyl benzoate, 3,5,5-trimethylhexyl benzoate,mixtures thereof, and the like. Specific commercial examples of suchbenzoic acid alkyl esters include VELTA® 262 (isodecyl benzoate) andVELTA® 368 (2-ethylhexyl benzoate), available from Vlesicol ChemicalCorporation. Examples of ester-alcohols include hydroxyalkyl esters ofalkanoic acids where the alkyls group, which can be straight orbranched, substituted or unsubstituted, independently have from about 2to about 30 carbon atoms, such as 2,2,4-trimethylpentane-1,3-diolmonoisobutyrate. Specific commercial examples of such ester-alcoholsinclude TEXANOL® (2,2,4-trimethylpentane-1,3-diol monoisobutyrate)available from Eastman Chemical Company. Examples of glycol-ether typesolvents include diethylene glycol monomethylether acetate, diethyleneglycol monobutylether acetate, butyl carbitol acetate (BCA), and thelike. Examples of long-chain aliphatic alcohols include those where thealkyl group is from about 5 to about 20 carbon atoms, such asethylhexanol, octanol, dodecanol, and the like. Examples of aromaticalcohols include benzyl alcohol, and the like.

In embodiments, the coalescent agent (or coalescence aid agent)evaporates during later stages of the emulsion aggregation process orduring coalescence, such as during the heating step that is generallynear or above the glass transition temperature of the sulfonatedpolyester resin. The final composite powders are thus free of, oressentially or substantially free of, any remaining coalescent agent. Tothe extent that any remaining coalescent agent may be present in thefinal powder composites, the amount of remaining coalescent agent issuch that it does not affect any properties or performance of thecomposite powders.

The coalescent agent can be added prior to the coalescence in anydesired or suitable amount. For example, the coalescent agent can beadded in an amount of from about 0.01 to about 10 percent by weight,based on the solids content in the reaction medium. For example, thecoalescent agent can be added in an amount of from about 0.05 or fromabout 20.0, from about 0.1 to about 10.0 percent by weight, or fromabout 0.5 to about 5.0 percent by weight, based on the solids content inthe reaction medium. In embodiments, the coalescent agent can be addedat any time between aggregation and coalescence or upfront beforeheating.

Optional additives such as waxes, pigments, ceramics, carbon fiber ornanotubes, and fillers may be included in the composite powder. Theseadditives may be added prior to or during the aggregation step orupfront before heating. The amount of additives present in the compositepowder may be from about 0% to about 30%, from about 0% to about 20%, orfrom about 0% to about 10% by weight of the total weight of thecomposite powder.

Method of Making

The present disclosure also provides methods for making the compositepowder described herein. The method to prepare the microparticles frompolymeric coated sulfonated polyester-silver nanoparticles SPE-AgNPs issimilar to the process known to generate toner particles (emulsionaggregation or EA). Particles of narrow size distribution andcontrollable particle size can be achieved with the aid of aggregatingagents such as zinc acetate, magnesium chloride salts, aluminum sulfateand polyaluminum chloride (PAC). The particle morphology can becontrolled via temperature, time, and stirring to provide particles thatrange from an irregularly shaped or an imperfect spherical to a near orperfect spherical.

The method comprising heating a sulfonated polyester resin in anorganic-free solvent, adding a solution of silver (I) ion to the heatedresin in the organic-free solvent to form a mixture, adding a solutionof a reducing agent to the mixture, thereby forming an emulsion of coreparticles comprising a sulfonated polyester matrix and a plurality ofsilver nanoparticles disposed within the sulfonated polyester matrix;adding a styrene monomer and initiator to the emulsion of core particlesto form a shell polymer disposed about the core particles, therebyforming a composite structure; aggregating the emulsion of compositeparticles to form aggregated particles; coalescing the aggregatedparticles to form coalesced particles; and washing the coalescedparticles, thereby forming the composite powder. The term “organic-freesolvent” refers to media that does not contain any organic solvent, anaqueous media such as water is considered to be an organic-free solvent.

In embodiments, heating is conducted at a temperature from about 65° C.to about 90° C. Temperatures in this range are appropriate for both theinitial dissolution of the polymer resin and subsequent reduction in thepresence of silver ion.

In embodiments, a source of silver (I) ion is selected from silvernitrate, silver sulfonate, silver fluoride, silver perchlorate, silverlactate, silver tetrafluoroborate, silver oxide, silver acetate. Silvernitrate is a common silver ion precursor for the synthesis of AgNPs.

In embodiments, the reducing agent is selected from ascorbic acid,trisodium citrate, glucose, galactose, maltose, lactose, gallic acid,rosmarinic acid, caffeic acid, tannic acid, dihydrocaffeic acid,quercetin, sodium borohydride, potassium borohydride, hydrazine hydrate,sodium hypophosphite, hydroxylamine hydrochloride. In embodiments,reducing agents for the synthesis of AgNPs may include sodiumborohydride or sodium citrate. Selection of appropriate reducing agentmay provide access to desirable nanoparticle morphologies. For example,ascorbic acid was observed to provide silver nanoplate forms during astudy directed to quantitation of vitamin C tablets. Rashid et al. J.Pharm. Sci. 12(1):29-33 (2013).

In embodiments, methods may include during the step of adding thestyrene monomer, also adding at least one vinyl monomer selected fromthe group consisting of methyl acrylate, ethyl acrylate, butyl acrylate,isobutyl acrylate, dodecyl acrylate, n-octyl acrylate, 2-ethylhexylacrylate, 2-chloroethyl acrylate, phenyl acrylate, β-carboxyethylacrylate, methyl α-chloro acrylate, methyl methacrylate, ethylmethacrylate, butyl methacrylate, butadiene, isoprene,methacrylonitrile, acrylonitrile, methyl vinyl ether, vinyl isobutylether, vinyl ethyl ether, vinyl acetate, vinyl propionate, vinylbenzoate, vinyl butyrate, vinyl methyl ketone, vinyl hexyl ketone, andmethyl isopropenyl ketone, vinylidene chloride, vinylidene chlorofluoride, N-vinylindole, N-vinyl pyrrolidene, acrylic acid, methacrylicacid, acrylamide, methacrylamide, vinyl pyridine, vinyl pyrrolidone,vinyl N-methylpyridinium chloride, vinyl naphthalene, p-chlorostyrene,vinyl chloride, vinyl fluoride, ethylene, propylene, butylene, andisobutylene.

In embodiments, methods disclosed herein may be particularly well-suitedfor making composites with relatively low solids content. Under suchconditions, silver ion and reducing agent may readily diffuse throughthe polymer matrix. In the case of silver ion, such ready diffusion mayimprove uniformity of distribution of silver throughout the matrix. Thecomposite powders may be then fabricated into filaments. The compositefilament of the present disclosure may be manufactured using anextrusion process. The composite powders may be first loaded into a meltflow index (MFI) instrument (also referred to as an extrusionplastometer) and equilibrated at a temperature of from about 60° C. toabout 250° C., from about 60° C. to about 190° C., or from about 80° C.to about 150° C., for a period of time, such as from about 1 to about 90minutes, from about 1 to about 60 minutes, from about 5 to about 45minutes. After equilibration, the material obtained may be then extrudedwith a weight in a range of from about 1 kg to about 30 kg, from about 1kg to about 20 kg, or from about 2 kg to about 10 kg, through a 0.5-5 mmdiameter die to fabricate the FDM filament. In embodiments, thecomposite filament is in the form of a cylinder with a diameter of, forexample, about 0.5 mm to about 5.0 mm, about 1.5 mm to about 3.0 mm,about 1.75 mm to about 3.0 mm. The length of the composite filament canbe in any length, for example, for testing purposes, from about 2 ft toabout 100 ft, from about 2 ft to about 50 ft, from about 5 ft to about20 ft, and for commercial purposes, from about 50 ft to 2000 ft, fromabout 300 ft to about 1500 ft, or from about 400 ft to about 1300 ft.

The process of filament fabrication merely changes the physical appearof the composite and does not alter the material or content of thecomposite. Thus, the filament of the present disclosure comprises thesame sulfonated polyester matrix and silver nanoparticles as describedherein. In embodiments, the filament comprises the same sulfonatedpolyester-silver core nanoparticles as described herein. In embodiments,the filament comprises the same sulfonated polyester-silver corenanoparticles having a shell polymer disposed over as described herein.

In embodiments, a loading of silver nanoparticle is present in thecomposite filaments in a range from about 0.5 ppm to about 50,000 ppm,from about 5 ppm to about 5,000, from about 10 ppm to about 2,500, ppm,or from about 50 ppm to about 1,000 ppm. Loading concentrations ofsilver within this range can be used for antibacterial applications.Lower concentrations of silver might be sufficient for catalyticapplications; concentrations of AgNPs as low as 1 ppm have been used.Ghosh, S. K. et al. Langmuir. 18(23):8756-8760 (2002).

In embodiments, there are provided articles comprising a plurality ofcomposite filament as described herein, the composite filaments maycomprise a core particle comprising a sulfonated polyester matrix and aplurality of silver nanoparticles dispersed throughout the matrix and ashell polymer disposed about the core particle.

The properties of the composite herein make them useful in variousapplications including, without limitation, electronics components,optical detectors, chemical and biochemical sensors and devices. Theability to miniaturize any of these materials is a major benefit ofusing the nanoscale composite structures herein. Other areas of interestthat employ the composite powder herein include, without limitation,antibacterial applications, optical bi-stability, textilesphotoresponsivity, environmental, biological, medicine (membranes andseparation devices), functional smart coatings, fuel and solar cells,and as catalysts.

The following Examples are being submitted to illustrate embodiments ofthe present disclosure. These Examples are intended to be illustrativeonly and are not intended to limit the scope of the present disclosure.Also, parts and percentages are by weight unless otherwise indicated. Asused herein, “room temperature” refers to a temperature of from about20° C. to about 25° C.

EXAMPLES

General Process: Composite preparation involves dispersing a branchedsodio sulfonated polyester (BSPE) in water at about 90° C., followed byaddition of a silver nitrate solution and lastly a mild reducing agentsuch as trisodium citrate, ascorbic acid. The reduction of Ag(I) toAg(0) occurs after the addition of Ag(I) salt to the BSPE and isfacilitated by the reducing agent. AgNP-BSPE systems that aresynthesized via the trisodium citrate reductant route can also utilizethe citrate cap for further applications such as biosensors where thecitrate ligand is employed for analyte binding for quantitative orqualitative analysis of analyte concentration in a sample. Lastly, apolymeric monomer, such as a styrene monomer, along with an initiator(e.g., ammonium persulfate) is added to form a polymeric shell about thecore particle.

Example 1

This example describes the preparation of a branched sodio sulfonatedamorphous polyesters (BSPE) according to embodiments of the presentdisclosure.

A branched amorphous sulfonated polyester resin comprised of 0.425 moleequivalent of terephthalate, 0.080 mole equivalent of sodium5-sulfoisophthalic acid, 0.4501 mole equivalent of 1,2-propanediol, and0.050 mole equivalent of diethylene glycol, was prepared as follows. Ina one-liter Parr reactor equipped with a heated bottom drain valve, highviscosity double turbine agitator, and distillation receiver with a coldwater condenser was charged 388 grams of dimethylterephthalate, 104.6grams of sodium 5-sulfoisophthalic acid, 322.6 grams of 1,2-propanediol(1 mole excess of glycols), 48.98 grams of diethylene glycol, (1 moleexcess of glycols), trimethylolpropane (5 grams) and 0.8 grams ofbutyltin hydroxide oxide as the catalyst. The reactor was heated to 165°C. with stirring for 3 hours and then again heated to 190° C. over a onehour period, after which the pressure was slowly reduced fromatmospheric pressure to about 260 Torr over a one hour period, and thenreduced to 5 Torr over a two hour period. The pressure was then furtherreduced to about 1 Torr over a 30 minute period and the polymer wasdischarged through the bottom drain onto a container cooled with dry iceto yield 460 grams of sulfonated-polyester resin. The branchedsulfonated-polyester resin had a glass transition temperature measuredto be 54.5° C. (onset) and a softening point of 154° C.

Example 2

This Comparative Example shows the preparation of a BSPE core particlewith no silver and no styrene shell.

The reaction was carried out in a 3 necked, 500 mL round bottom flaskequipped with an overhead stirrer, reflux condenser, thermocouple, hotplate, and nitrogen entrance (the condenser acted as the nitrogen exit).125 mL of deionized water (DIW) was charged into the flask at roomtemperature (about 22° C.). The DIW was heated to 90° C. with stirringwhile nitrogen running through the solution (RPM=330). Then 50.0 g offinely ground, solid BSPE obtained from Example 1 was added to the DIW(RPM=400). The solution was stirred at 90° C. for 2 hours (RPM=400). AnBSPE emulsion was obtained and cooled to room temperature with stirring(RPM=400). The final appearance of the BSPE emulsion was a white, opaquesolution.

Example 3

This Comparative Example shows the formation of a styrene shell about aBSPE core particle with no silver dispersed within the core particle.

The reaction was carried out in a 3 necked, 500 mL round bottom flaskequipped with an overhead stirrer, reflux condenser, thermocouple, hotplate, and nitrogen entrance (the condenser acted as the nitrogen exit).About 240 mL of deionized water was charged into the flask at roomtemperature (22° C.). The heat was turned on and set to 90° C. andnitrogen was run through the system for 30 minutes (RPM=300). Once thetemperature had stabilized, 50.0 g of finely ground BSPE obtained fromExample 1 was added to the flask (RPM=300). The resulting solution wastranslucent with a blue tinge, which was left to stir for 2 hours. Thenthe set point was reduced to 75° C. Once the temperature had stabilized,3.6 g styrene (9% of total monomer) was added, followed by dropwiseaddition of ammonium persulfate solution (0.08 g ammonium persulfatedissolved in 10 mL deionized water) which acts as an initiator. Theaddition of ammonium persulfate solution causes a slight increase intemperature (exotherm). After the temperature had stabilized at 75° C.,36.40 g styrene monomer was added dropwise over 15 minutes to themixture. The resulting solution was white and opaque after monomeraddition was complete. The reaction was allowed to be stirred for 2hours at 75° C., and then allowed to cool to room temperature. The finalappearance was a white, opaque solution.

Example 4

This Example shows the formation of a styrene shell about a BSPE/AgNPcore composite prepared in the absence of a reducing agent.

The reaction was carried out in a 3 necked, 500 mL round bottom flaskequipped with an overhead stirrer, reflux condenser, thermocouple, hotplate, and nitrogen entrance (the condenser acted as the nitrogen exit).About 235 mL of deionized water was charged into the flask at roomtemperature (22° C.). The heat was turned on and set to 90° C. andnitrogen was run through the system for 30 minutes (RPM=300). Once thetemperature had stabilized, 50.0 g of finely ground BSPE obtained fromExample 1 was added to the flask (RPM=330). The resulting mixture wastranslucent with a blue tinge, which was left to stir for 2 hours. 0.12g of AgNO₃ was dissolved in 10 mL deionized water and added to thesolution dropwise (1 drop/second). A colour change to dark brown with ayellow tinge was observed. After the completion of AgNO₃ addition, theset point was reduced to 75° C. Once the temperature had stabilized, 3.6g styrene (9% of total monomer) was added, followed by dropwise additionof an ammonium persulfate solution (0.08 g ammonium persulfate dissolvedin 5 mL deionized water) which acts as an initiator. Ammonium persulfatesolution causes a slight increase in temperature (exotherm). After thetemperature had stabilized at 75° C., 36.40 g styrene monomer was addeddropwise over 40 minutes to the mixture. The resulting solution waslight pink and opaque after monomer addition was complete. The reactionwas allowed to be stirred for 2 hours at 75° C. and then allowed to coolto room temperature. The final appearance was a light pink, opaquesolution.

Example 5

This Example shows the formation of a styrene shell about a BSPE/AgNPcore particle prepared in the presence of the reducing agent oleic acid.

The reaction was carried out in a 3 necked, 500 mL round bottom flaskequipped with an overhead stirrer, reflux condenser, thermocouple, hotplate, and nitrogen entrance (the condenser acted as the nitrogen exit).About 118 mL of deionized water and 0.25 g oleic acid were charged intothe flask at room temperature (22° C.). The heat was turned on and setto 90° C. and nitrogen was run through the system for 30 minutes(RPM=300). Once the temperature had stabilized, 25.0 gram of finelyground BSPE obtained from Example 1 was added to the flask (RPM=250).The resulting solution was translucent and purple/brown in colour. Themixture was left to stir for 2 hours. 0.12 g of AgNO₃ was dissolved in 5mL deionized water and added to the solution dropwise (1 drop/second). Acolour change to dark brown was observed. After the completion of AgNO₃addition, the set point was reduced to 75° C. (RPM=330). Once thetemperature had stabilized, 20.0 g of styrene was added, followed bydropwise addition of an ammonium persulfate solution (0.05 g ammoniumpersulfate dissolved in 2 mL deionized water) which acts as aninitiator. The reaction was run for 4 hours at 75° C., and then foranother 16.5 hours at 60° C. (RPM=330). The resulting solution was thenallowed to cool to room temperature. The final appearance was a brownopaque solution.

Example 6

This Example shows the formation of a styrene shell about a BSPE/AgNPcore particle prepared in the presence of the reducing agentglutathione.

The reaction was carried out in a 3 necked, 500 mL round bottom flaskequipped with an overhead stirrer, reflux condenser, thermocouple, hotplate, and nitrogen entrance (the condenser acted as the nitrogen exit).About 240 mL of deionized water was charged into the flask at roomtemperature (22° C.). The heat was turned on and set to 90° C. andnitrogen was run through the system for 30 minutes (RPM=300). Once thetemperature had stabilized, 35.0 g of finely ground BSPE obtained fromExample 1 was added to the flask. The resulting solution was opaque andwhite with a blue tinge. The BSPE was mixed for 1 hour to disperse it.0.12 g of AgNO₃ was dissolved in 5 mL deionized water and added to thesolution dropwise (1 drop/second). A color change to brown was observed.After the completion of AgNO₃ addition, the set point was reduced to 75°C. Once the temperature had stabilized, 0.0353 g of glutathione(reducing/stabilizing agent) was added. The solution became dark brown.Subsequently, 3.27 g styrene (8% of total monomer) was added to the darkbrown solution (RPM=390), followed by dropwise addition of an ammoniumpersulfate solution (0.1 g ammonium persulfate dissolved in 5 mLdeionized water) which acts as an initiator. A color change to purplewas observed. After 5 minutes, 36.73 g of styrene monomer was addeddropwise over 40 minutes. The solution was pale purple after thecompletion of monomer addition. The reaction was run for 4 hours at 75°C. (RPM=390). The resulting solution was then allowed to cool to roomtemperature. The final appearance was a grey, opaque solution.

Example 7

This Example shows the formation of a styrene shell about a BSPE/AgNPcore particle prepared in the presence of the reducing agent.

The reaction was carried out in a 3 necked, 500 mL round bottom flaskequipped with an overhead stirrer, reflux condenser, thermocouple, hotplate, and nitrogen entrance (the condenser acted as the nitrogen exit).248 mL of DIW was charged into the flask at room temperature (22° C.).The heat was turned on set to 90° C. and nitrogen was run through thesystem (RPM=300). Once the temperature had stabilized, 21.61 g of solidBSPE-1 was added to the system in a finely ground state (RPM=300). Thesolution became hazy and had a pale blue tinge. After 0.5 hrs., 0.1184 gAgNO₃ dissolved in 2 mL DIW was added dropwise to the solution at a rateof approx. 1 drop/second (RPM=300). The solution became green/brown.After 0.5 hrs, 5 mL of 1% (w/w %) trisodium citrate solution (reducingagent) was added to the system dropwise at a rate of 1 drop/second. Uponcomplete addition, the solution was stirred at 90° C. for 2 hours(RPM=300). The solution was allowed to cool to room temperature(RPM=300). The final appearance was a brown, opaque solution.

Table 1 shows particle characterization for coated and uncoated coreparticles comprising sulfonated polyester silver nanoparticles with orwithout silver nanoparticles. The particle size and zeta potential ofall samples are comparable except for a couple of outliers (e.g.,Example 5's zeta potential and Example 6's particle size). Example 5 hasa higher zeta potential compared to the other samples due to thecontribution of the carboxyl groups from oleic acid which slightlyincreases the negative surface charge of the nanoparticles. Example 6contains a higher loading of styrene and glutathione which bothcontribute to the higher particle size compared to the other samples.

TABLE 1 % Styrene Loading Loading Particle Zeta Reducing relative toTheoretical [AgNO₃] [AgNO₃] Actual % Size D50 Potential Example AgentBSPE % Solids (M) (w/w %) Solids (nm) (mV) 2 None 0 28.57% 0 0.00%29.46% 31.8 −58.9 3 None 44 26.49% 0 0.00% 26.54% 30.1 −60.1 4 None 4426.51% 2.08E−03 0.04% 26.57% 31.3 −61.8 5 oleic acid 44 26.65% 4.87E−030.07% 22.88% 34.3 −65.9 6 glutathione 53 23.14% 2.44E−03 0.04% 22.00%47.3 −59.0 7 Trisodium 0 8.00% 2.73E−03 0.05% 7.58% 25.4 −55.8 citrate

Example 8

This Example shows the preparation of a styrenated BSPE/AgNP powder(i.e., styrenic shell/BSPE/AgNP powder)

In a 2 L glass reactor, a latex emulsion containing 200 g ofstyrenic/BSPE-AgNP composite obtained from Example 5 and 200 g ofdeionized water is premixed to give total solids of 13.3%, the pH isadjusted from about 5.0 to 3.0 with 0.3 M nitric acid. The slurry isthen homogenized using an IKA ULTRA TURRAX T50 homogenizer operating atabout 3,000-4,000 RPM. During homogenization, about 28 g of a flocculentmixture containing about 2.8 g polyaluminum chloride mixture and about25.2 g 0.02 M nitric acid solution is added to the slurry. Thereafter,the 2 L glass reactor is transferred to a heating mantle; the RPM is setto 230 and heated to a temperature of about 50° C. where samples aretaken to determine the average toner particle size. Once the particlesize of the slurry is about 15 microns as measured with a CoulterCounter is achieved, freezing begins with the pH of the slurry beingadjusted to about 4.5-5.0 using a 4% NaOH solution while also decreasingthe reactor RPM to 75. The reactor temperature is ramped to 96° C. Onceat the coalescence temperature, the slurry is coalesced for about 3hours until the particle circularity is between 0.975-0.980 as measuredby the Flow Particle Image Analysis (FPIA) instrument. The slurry isthen cooled. The final particle size of the slurry is about 15.5microns, GSDv 1.25, GSDn 1.25 and a circularity of 0.981. The slurry isthen discharged from the reactor and the particles are filtered from themother liquor and washed 2 times with deionized (DIW). The final slurryis re-dispersed into 200 mL of deionized water, frozen viashell-freezer, and placed on drier for 3 days to result in dry particlesto be used for FDM additive manufacturing.

Example 9

This Example shows the fabrication of filaments

The dried particles obtained from Example 8 were fed into the melt flowindex (MFI) instrument (extrusion plastometer) and equilibrated at 90°C. for 6 minutes. The material was then extruded with a 17 kg weightthrough a 2 mm diameter die to fabricate the FDM filament forantibacterial testing.

Example 10

This Example tests the robustness of the hybrid composites (i.e.,styrenic shell/BSPE/AgNPs) obtained from Examples 3-7 (A) SolventResistance

The solvent resistance test tests the ability of a composite to resistchemicals or solvents that would otherwise degrade the polymer.

A pellet was made by compressing approximately 0.50 g of sample under 5tons of pressure for 5 minutes using a hand press. The initial weight ofthe pellet was measured. 10 mL of solvent was added to the vials. After24 hours, the solutions were inverted 5 times. After 48 hours, thepellet was placed on a weighing dish. The pellet was allowed to air dry.The final mass of the pellet was measured and recorded once it achievedconstant weight (+/−0.0001 g).

BSPE alone cannot withstand treatment with solvents with a highdielectric constant/high polarity (i.e., methanol) very well. Althoughit was not completely dissolved after 48 hours, the physical propertieschanged dramatically to a stringy gelatinous blob.

A pellet of pure poly(styrene) sample kept its form as a pellet and wasalmost completely undissolved. Example 4 had good resistance to methanolcompared to other hybrid nanocomposites; this sample had well dispersedAgNPs within the organic matrix as seen in FIG. 2.

Overall, the styrenation of sulfonated polyester AgNPs improved itsresistance to methanol. All the BSPE/Styrene AgNPs hybrids remained asdistinct pellets in methanol with 85-90% of the pellet undissolved after48 hrs. When less polar (low dielectric constant) solvents were used forthe resistance test most of the samples dissolved.

Table 2 shows results of the solvent resistance results forBSPE/Styrenated AgNPs compared to 100% BSPE or polystyrene.

% Initial Final Dis- Appearance Appearance Vial Example Solvent solvedof Pellet of Pellet 1 3 THF 100.0% white completely dissolved 2 MEK100.0% white completely dissolved 3 methanol 10.0% white White 4 5 THF100.0% brown completely dissolved 5 MEK 100.0% brown completelydissolved 6 methanol 11.5% brown brown, some cracking on the sides 7 4THF 100.0% off white completely dissolved 8 MEK 100.0% off whitecompletely dissolved 9 methanol 7.0% off white white, some cracking onsides 10 6 THF 100.0% beige completely dissolved 11 MEK 100.0% beigecompletely dissolved 12 methanol 12.0% beige Beige 13 2 (BSPE THF 100.0%white completely only) dissolved 14 MEK 100.0% white completelydissolved 15 methanol gelled white sticky/ stringy white polymer, not apellet 16 Poly- THF 100.0% white completely styrene; dissolved 17 SigmaMEK 100.0% white completely Aldrich dissolved 18 Mw = 13K methanol 1.0%white white pellet

(B) Thermal Degradation Resistance

As shown in Table 3, the polymer shell-protected (e.g.,styrenic/BSPE/AgNPs obtained from Example 6) shows only about 50%degradation at 400° C. by thermogravimetric analysis (TGA), whileuncoated BSPE-AgNP composites BSPE alone are 80% decomposed by 400° C.The thermal stability of the styrene-coated BSPE/AgNPs appears to bemore complex than that of polystyrene alone. The first major mass lossof the hybrid composite starts around 300° C. (30.86%) but becomes morestable and degrades much slower than uncoated samples and polystyrenecontrol.

TABLE 3 % weight loss Styrenic/ based on TGA BSPE/ Control data (RT toAgNPs BSPE-Ag BSPE Control 700° C. heating (Example (Example (ExamplePoly- of 100% of sample) 6) 7) 2) styrene Weight (%) loss 30.86% 10.04%17.26% 0.92% from start to 300° C. Weight (%) loss 46.49% 79.63% 82.05%98.85%* from 300 to 400° C. Weight (%) loss 93.38% 89.53% 89.30% from400 to 500° C. Weight (%) loss 98.41% 97.15% 97.76% 0.00% from 500 to700° C. Residual (%) 1.60% 2.84% 2.21% 0.15% Total 100.01% 99.99% 99.96%99.92% *Polystyrene degrades as one single peak starting at around 300°C.

(C) Acid/Base Resistance

The acid/base resistance test tests the ability of a composite acids andbases that would otherwise degrade the composite.

A pellet was made by compressing approximately 0.50 g of sample under 5tons of pressure for 5 minutes using a hand press. The initial weight ofthe pellet was measured. 10 mL of acid/base (10% Nitric acid, 10% NaOHor 30% Sulfuric acid) was added to the vials. After 96 hours, the pelletwas placed on a weighing dish. The pellet was allowed to air dry for 3days. The final mass of the pellet was measured and recorded. Thisprocedure was adapted from an article published in Industrial andEngineering Chemistry. Church, J. M et al. Ind. Eng. Chem., 47(12):2456-2462 (1955).

Table 4 shows Acid/Base Resistance results for BSPE/Styrenated AgNPscompared to 100% BSPE or polystyrene. The value for the % dissolved forsample from Example 3 was corrected to account for 5% sample loss duringmeasurement.

The results of the soak test show that composites are largelysusceptible to base catalyzed degradation. The sample of BSPE aloneshowed the highest amount of it's initial mass dissolved in dissolve in10% NaOH. In comparison, styrene alone did not dissolve. TheBSPE-Styrene (Example 3) and BSPE-Styrene-Silver samples (Examples 5 and6) were less susceptible to degradation in an alkaline environment thanthe sample that was not styrenated. Samples did not dissolve appreciablyin acidic environments. The higher amount of dissolved material in acidfor Example 6 is likely the result of the hydrolysis of glutathione inacid. Olson, C. K. et al. J. Biol. Chem., 186:731-735 (1950).

In sum, the addition of a styrene shell to the BSPE/AgNPs results in animprovement under basic conditions by 20 to 30%. No significantimprovement is observed in acidic environments. In some cases, BSPE withembedded AgNPs may still become susceptible to alkali environments whenthe ester linkages are split to an acid and alcohol by hydrolysis.Additionally the hydrolysis may be acid or base catalyzed (e.g., polymercoated materials exposed to basic or acidic cleaning products or acidrain). Polymerizing a shell of polystyrene, around the BSPE/AgNP coreprovides substantially improved rigidity and strength of theorganic/inorganic hybrid composite core materials.

TABLE 4 % change relative % to BSPE Vial Example Acid/Base Dissolved(Example 2) 1 3 10% Nitric Acid 0.0% 2 10% NaOH 32.2%  30.9% 3 30%Sulfuric Acid 0.0% 4 5 10% Nitric Acid 4.3% 5 10% NaOH 45.8%  17.2% 630% Sulfuric Acid 4.1% 7 6 10% Nitric Acid 5.4% 8 10% NaOH 35.6%  27.4%9 30% Sulfuric Acid 14.5%  10 2 (BSPE 10% Nitric Acid 2.0% 11 only) 10%NaOH 63.0%    0% 12 30% Sulfuric Acid 0.00%  13 Polystyrene; 10% NitricAcid 0.0% 14 Sigma 10% NaOH 0.0% 15 Aldrich 30% Sulfuric Acid 0.0% Mw =13K

Example 11

This Example shows the antibacterial testing of filaments

A 200 mm Pyrex® glass tube is filled with Bacto™ Tryptic Soy Broth and afilament from Example 8 is placed in the glass tube. The glass tube issealed with a rubber stopper and being incubated at 37° C. and 90%humidity for 14 days. A control sample of BSPE filament (from Example 3)containing no AgNPs is also treated to the same incubation procedure.After the incubation period, the tubes are visually analyzed forturbidity. Prior to any filament incubation, the soy broth or TSB istransparent. Once the TSB is exposed to bacteria or fungi, the organismswill turn the liquid turbid due to reproduction/multiplication ofbacteria. Another indicator of bacterial growth is accumulation ofprecipitation that will settle to the bottom of the test tube. Thefilament made with the BSPE-AgNPs in Example 4 shows no signs ofbacterial contamination while the non-AgNP containing BSPE show bothturbidity and precipitation indicating a lack of antibacterial activity.

What is claimed is:
 1. A composite filament comprising: a core particlecomprising: a sulfonated polyester matrix; and a plurality of silvernanoparticles dispersed within the matrix; and a shell polymer disposedabout the core particle; wherein the silver nanoparticle is present inthe composite filament in a range from about 0.5 ppm to about 50,000ppm; and further wherein the composite filament has a diameter of fromabout 0.5 mm to about 5 mm.
 2. The composite filament of claim 1,wherein the sulfonated polyester has a glass transition (Tg) temperatureof from about 45° C. to about 95° C.
 3. The composite filament of claim1, wherein the sulfonated polyester matrix comprises a branched polymer.4. The composite filament of claim 1, wherein the sulfonated polyestermatrix comprises a linear polymer.
 5. The composite filament of claim 1,wherein the composite filament is in the form of a cylinder having adiameter of about 0.5 mm to about 5.0 mm.
 6. The composite filament ofclaim 1, wherein the sulfonated polyester matrix comprises hydrogen or asalt of a random sulfonated polyester, wherein the sulfonated polyesteris selected from poly(1,2-propylene-5-sulfoisophthalate),poly(neopentylene-5-sulfoisophthalate),poly(diethylene-5-sulfoisophthalate),copoly(1,2-propylene-5-sulfoisophthalate)-copoly-(1,2-propylene-terephthalatephthalate),copoly(1,2-propylene-diethylene-5-sulfoisophthalate)-copoly-(1,2-propylene-diethylene-terephthalatephthalate),copoly(ethylene-neopentylene-5-sulfoisophthalate)-copoly-(ethylene-neopentylene-terephthalate-phthalate),copoly(propoxylated bisphenol A)-copoly-(propoxylated bisphenolA-5-sulfoisophthalate),copoly(ethylene-terephthalate)-copoly-(ethylene-5-sulfo-isophthalate),copoly(propylene-terephthalate)-copoly-(propylene-5-sulfo-isophthalate),copoly(diethylene-terephthalate)-copoly-(diethylene-5-sulfo-isophthalate),copoly(propylene-diethylene-terephthalate)-copoly-(propylene-diethylene-5-sulfoisophthalate),copoly(propylene-butylene-terephthalate)-copoly(propylene-butylene-5-sulfo-isophthalate),copoly(propoxylated bisphenol-A-fumarate)-copoly(propoxylated bisphenolA-5-sulfo-isophthalate), copoly(ethoxylatedbisphenol-A-fumarate)-copoly(ethoxylatedbisphenol-A-5-sulfo-isophthalate), copoly(ethoxylatedbisphenol-A-maleate)-copoly(ethoxylatedbisphenol-A-5-sulfo-isophthalate), copoly(propylene-diethyleneterephthalate)-copoly(propylene-5-sulfoisophthalate),copoly(neopentyl-terephthalate)-copoly-(neopentyl-5-sulfoisophthalate),and mixtures thereof.
 7. The composite filament of claim 6, wherein thesalt is selected from the group consisting of sodium, lithium andpotassium.
 8. The composite filament of claim 1, wherein the sulfonatedpolyester matrix comprises a polyol monomer unit selected from the groupconsisting of trimethylolpropane, 1,2-propanediol, diethylene glycol,and combinations thereof.
 9. The composite filament of claim 1, whereinthe sulfonated polyester matrix comprises a diacid monomer unit selectedfrom the group consisting of terephthalic acid, sulfonated isophthalicacid, and combinations thereof.
 10. The composite filament of claim 1,wherein the shell polymer comprises a styrene monomer.
 11. The compositeof filament claim 1, wherein the shell polymer further comprises atleast one vinyl monomer selected from the group consisting of methylacrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, dodecylacrylate, n-octyl acrylate, 2-ethylhexyl acrylate, 2-chloroethylacrylate, phenyl acrylate, β-carboxyethyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate,butadiene, isoprene, methacrylonitrile, acrylonitrile, methyl vinylether, vinyl isobutyl ether, vinyl ethyl ether, vinyl acetate, vinylpropionate, vinyl benzoate, vinyl butyrate, vinyl methyl ketone, vinylhexyl ketone, and methyl isopropenyl ketone, vinylidene chloride,vinylidene chloro fluoride, N-vinylindole, N-vinyl pyrrolidene, acrylicacid, methacrylic acid, acrylamide, methacrylamide, vinyl pyridine,vinyl pyrrolidone, vinyl N-methylpyridinium chloride, vinyl naphthalene,p-chlorostyrene, vinyl chloride, vinyl fluoride, ethylene, propylene,butylene, and isobutylene.
 12. A method of producing a compositefilament, comprising: heating a sulfonated polyester resin in anorganic-free solvent; adding a solution of silver (I) ion to the heatedresin in the organic-free solvent to form a mixture; adding a solutionof a reducing agent to the mixture, thereby forming an emulsion of coreparticles comprising a sulfonated polyester matrix and a plurality ofsilver nanoparticles disposed within the sulfonated polyester matrix;adding a styrene monomer and initiator to the emulsion of core particlesto form a shell polymer disposed about the core particles, therebyforming a composite structure; aggregating the emulsion of compositeparticles to form aggregated particles; coalescing the aggregatedparticles to form coalesced particles; washing the coalesced particles,thereby forming a composite powder; and extruding the composite powderto produce the composite filament.
 13. The method of claim 12, whereinthe heating of the sulfonated polyester resin is conducted at atemperature from about 65° C. to about 90° C.
 14. The method of claim12, wherein the aggregating is conducted at a temperature of from about30° C. to about 80° C.
 15. The method of claim 12, wherein thecoalescing is conducted at a temperature of from about 30° C. to about95° C.
 16. The method of claim 12, wherein a source of silver (I) ion isselected from silver nitrate, silver sulfonate, silver fluoride, silverperchlorate, silver lactate, silver tetrafluoroborate, silver oxide andsilver acetate.
 17. The method of claim 12, wherein during the step ofadding the styrene monomer, also adding at least one vinyl monomerselected from the group consisting of methyl acrylate, ethyl acrylate,butyl acrylate, isobutyl acrylate, dodecyl acrylate, n-octyl acrylate,2-ethylhexyl acrylate, 2-chloroethyl acrylate, phenyl acrylate,β-carboxyethyl acrylate, methyl a-chloro acrylate, methyl methacrylate,ethyl methacrylate, butyl methacrylate, butadiene, isoprene,methacrylonitrile, acrylonitrile, methyl vinyl ether, vinyl isobutylether, vinyl ethyl ether, vinyl acetate, vinyl propionate, vinylbenzoate, vinyl butyrate, vinyl methyl ketone, vinyl hexyl ketone, andmethyl isopropenyl ketone, vinylidene chloride, vinylidene chlorofluoride, N-vinylindole, N-vinyl pyrrolidene, acrylic acid, methacrylicacid, acrylamide, methacrylamide, vinyl pyridine, vinyl pyrrolidone,vinyl N-methylpyridinium chloride, vinyl naphthalene, p-chlorostyrene,vinyl chloride, vinyl fluoride, ethylene, propylene, butylene, andisobutylene.
 18. The method of claim 12, wherein the sulfonatedpolyester matrix comprises hydrogen or a salt of a random sulfonatedpolyester, wherein the sulfonated polyester is selected frompoly(1,2-propylene-5-sulfoisophthalate),poly(neopentylene-5-sulfoisophthalate),poly(diethylene-5-sulfoisophthalate),copoly(1,2-propylene-5-sulfoisophthalate)-copoly-(1,2-propylene-terephthalatephthalate),copoly(1,2-propylene-diethylene-5-sulfoisophthalate)-copoly-(1,2-propylene-diethylene-terephthalatephthalate),copoly(ethylene-neopentylene-5-sulfoisophthalate)-copoly-(ethylene-neopentylene-terephthalate-phthalate),copoly(propoxylated bisphenol A)-copoly-(propoxylated bisphenolA-5-sulfoisophthalate),copoly(ethylene-terephthalate)-copoly-(ethylene-5-sulfo-isophthalate),copoly(propylene-terephthalate)-copoly-(propylene-5-sulfo-isophthalate),copoly(diethylene-terephthalate)-copoly-(diethylene-5-sulfo-isophthalate),copoly(propylene-diethylene-terephthalate)-copoly-(propylene-diethylene-5-sulfoisophthalate),copoly(propylene-butylene-terephthalate)-copoly(propylene-butylene-5-sulfo-isophthalate),copoly(propoxylated bisphenol-A-fumarate)-copoly(propoxylated bisphenolA-5-sulfo-isophthalate), copoly(ethoxylatedbisphenol-A-fumarate)-copoly(ethoxylatedbisphenol-A-5-sulfo-isophthalate), copoly(ethoxylatedbisphenol-A-maleate)-copoly(ethoxylatedbisphenol-A-5-sulfo-isophthalate), copoly(propylene-diethyleneterephthalate)-copoly(propylene-5-sulfoisophthalate),copoly(neopentyl-terephthalate)-copoly-(neopentyl-5-sulfoisophthalate),and mixtures thereof.
 19. An article comprising: a composite filamentcomprising: a core particle comprising: a sulfonated polyester matrix;and a plurality of silver nanoparticles dispersed within the matrix; anda shell polymer disposed about the core particle; wherein the silvernanoparticle is present in the composite filament in a range from about0.5 ppm to about 50,000 ppm; and further wherein the composite powderhas a particle size of from about 10 microns to about 300 microns. 20.The article of claim 19, wherein the article is selected from the groupconsisting of a biochemical sensor, an optical detector, anantibacterial, a textile, a cosmetic, an electronic component, a fiber,and a cryogenic superconducting material.